Power storage system

1. A power storage system comprising: a plurality of unit modules connected in parallel, the unit modules each composed of a power storage device and a control device capable of managing a status of the power storage device; an electrical load whose driving is controlled by using powers of the power storage devices; and an integration control device connected to the electrical load and the control devices of the unit modules, wherein the control device of each of the unit modules obtains a current, a voltage, and a temperature as the status information of the power storage device; wherein a current limit value calculated by the control device of each of the unit modules is based on the status information and includes a discharge current limit value and a charge current limit value of each of the unit modules; and wherein the integration control device: compares the obtained pieces of status information with one another and defines a worst value to control the driving of the electrical load, wherein the worst value is one of the pieces of status information that has the largest deviation degree from a regular range of the pieces of status information, and wherein the pieces of status information are the current, the voltage, and the temperature, and further performs the control so that an average current equal to a sum of the currents of all the unit modules divided by the number of the unit modules falls between a maximum value among the discharge current limit values in current limitation and a minimum value among the charge current limit values in the current limitation.